1. Field of the Invention
The present invention relates to a light emitting display, and more particularly, to a light emitting display that employs high current to enhance data programming speed, so that the display can have a large size and represent a high gradation.
2. Description of Related Art
Various flat panel displays have recently been developed as alternatives to the relatively heavy and bulky cathode ray tube (CRT) display. The flat panel display includes a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), a light emitting display, etc.
The light emitting display includes a plurality of light emitting devices, each light emitting device has a structure that an emission layer is placed between a cathode electrode and an anode electrode. Here, an electron and a hole are injected into the emission layer and recombined to create an exciton, and light is emitted when the exciton falls to a lower energy level.
Such a light emitting display is classified into an inorganic light emitting display that includes an inorganic emission layer, and an organic light emitting display that includes an organic emission layer. In current programming type pixel circuit, the current needs to be minutely controlled, so that it takes relatively much time to charge the data signal in the capacitor. For example, in the case where a load provided on the data line has a capacitance of 30 pF, a time of several msec is needed to charge the load with a current of tens of nA to hundreds of nA. However, there is not enough charging time considering a line time of tens of μs. Particularly, when an image is displayed with low brightness, the applied current is also low, thus requiring much more charging time. Therefore, what is needed is an improved design for a light emitting display.